I. Field of the Invention
This invention relates generally to a biopsy instrument for collecting tissue samples through an endoscope, and more particularly to an instrument having bipolar electrodes for providing electrocoagulation to a site where a tissue sample has been taken.
II. Discussion of the Prior Art
In my earlier U.S. Pat. No. 5,603,711 and in a corresponding issued divisional U.S. Pat. No. 5,743,906, there is described a bipolar biopsy device that comprises an elongated tube dimensioned to fit through a working lumen of an endoscope, the tube having a proximal end and a distal end with a lumen extending therebetween. A handle is affixed to the proximal end of the elongated tube and a pair of end effectors are affixed to the distal end of the tube. A mechanical connection is made between the handle and the end effectors to cause them to open and close relative to one another in a scissors-like action. The end effectors each include a jaw member having an annular cutting edge surrounding a cup-like recess such that when a tissue sample to be excised is placed between the open jaws and then the handle is actuated to close them, the annular cutting blades mechanically sever through the tissue and the resulting severed piece of tissue resides in the cup-shape retainer.
In my earlier patents, which are hereby incorporated by reference herein, an insulating substrate is provided on the exterior surface of the annular cutting blades, and metal electrodes are provided on the insulating layer. Electrical conductors extend through the handle and the tubular member and connect to the two electrode surfaces so that when a voltage is applied, via an electrical surgical generator, an electrocautery voltage is developed across the two electrodes that are disposed individually on, but insulated from, the biopsy forceps jaws.
While the endoscopic bipolar biopsy forceps device described in my above-referenced patents simplifies the endoscopic biopsy procedure by obviating the need for frequent instrument exchanges in order to both cut and coagulate, the configuration of the end effectors makes the device more difficult and expensive to manufacture. Specifically, the steps of fitting and bonding the tissue cutting and retention cups within the outer supports while maintaining electrical isolation between the two involves a substantial number of operations and a substantially higher cost of manufacture as compared to a similar instrument made in accordance with the present invention.
It is accordingly a principal purpose of the present invention to provide an improved design for a bipolar biopsy forceps for use in endoscopic procedures.
Another object of the invention is to provide an endoscopic bipolar biopsy forceps that is easier to manufacture than prior art devices designed for the same purpose.
Yet another object of the invention is to provide an improved endoscopic bipolar biopsy forceps in which a coagulating voltage is applied between a metallic tissue cutting and retaining cup and an electrode affixed to the tissue cutting and retaining cup, but with an insulating layer therebetween.
Still another object of the invention is to provide an improved endoscopic bipolar biopsy forceps having applied electrodes and deposited or applied conductors for coupling the electrodes to a power source.